416 



MISS A. M. EVANS ON THE STRUCTURE AND OCCURRENCE 



All the Nocture observed were found to agree remarkably closely with 

 the condition found in Mamestra persicarice. The right maxillula of 

 M. persicarice (text-fig. 13) measures "51 nun. in length from the point (#.) 

 From this level to the apex of the hypopharynx the distance is '88 mm. 

 A thinly chit'inised plate (]>.) supports the outer wall of the maxillula to 

 which it is closely applied. It is fringed with freely projecting teeth. The 

 greatest width of the left lobe is "2 mm. The mental arm (a.m.) supports 

 the chitinous plate for the greater part of its length. 



The Rhopalocera investigated were not found to be strikingly different in 

 the character of the hypopharynx from the Heterocera. In Vanessa urticce 



Text-fig. 13. 



s.p. 



it ', .--^8 IBB-q.m 



-m. 



Mamestra persicarice. Labium and hypopharynx, dorso -lateral aspect, x 55. 

 a.m. Mental arm. h. Hypopharynx. Ip. Labial palp. m. Maxillula. 

 p. Plate supporting outer wall of maxillula. s.j>. Spinneret. 



this structure was of a form commonly occurring amongst the latter group. 

 This type, represented by Lagoa crispala, De Clryse (12. pi. 17. fig. 1), is 

 found in both micro and macro-lepidoptepa (p. 176). The fleshy lobes are 

 " covered with spines but devoid of all traces of blades." 



In jPieris brassicw and Philosamia cyntldq the maxillular lobes are very 

 large in proportion to the hypopharynx, the proximal half of which they 

 completely covered. 



Considerable attention was devoted to examination of the condition of the 



